CN111190971A

CN111190971A - ER graph drawing method and device based on adjacency list node state and priority

Info

Publication number: CN111190971A
Application number: CN201911406960.7A
Authority: CN
Inventors: 王功明; 王建华
Original assignee: Inspur Software Co Ltd
Current assignee: Inspur Software Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2020-05-22
Anticipated expiration: 2039-12-31
Also published as: CN111190971B

Abstract

The invention provides an ER graph drawing method and device based on adjacency list node state and priority, belonging to the fields of database, adjacency list, ER graph drawing, balance display, visual perception and the like, the invention comprises the following steps: s1: reading a database table structure; s2: generating an adjacency list-based entity relationship model; s3: and (4) drawing an ER graph by combining the node degrees and the visual position priority. The invention draws the nodes in descending order according to the node degree, scientifically utilizes the space area of the drawing interface, and can fully display the complex associated information of the nodes with larger degree; according to the method, the drawing sequence of the node associated entities is arranged based on visual perception smooth feeling, and meanwhile, the distribution condition of drawn associated entities at the adjacent positions of the nodes is considered, so that the fluency and the pleasure of a user for reading an ER graph can be improved; the display effect and the user experience of the ER map drawing are improved on the whole.

Description

ER graph drawing method and device based on adjacency list node state and priority

Technical Field

The invention relates to technologies of database, adjacency list, ER graph drawing, balance display and visual perception, in particular to an ER graph drawing method based on adjacency list node state and priority.

Background

The ER Diagram (Entity Relationship Diagram) is also called an Entity-contact Diagram, is a graphical description of an Entity Relationship model in database design, can visually display related entities and the contact among the entities, and is an effective method for describing an information world conceptual model.

The ER diagram is the best tool for related personnel to understand the database system and has important roles in the stages of database design, development, maintenance, reconstruction and the like. In the design process of the database, a modeler needs to understand an object to be processed according to an ER diagram, and finally forms a conceptual model meeting the requirement through continuous improvement of prototype deduction, scene analysis and iterative optimization. In the process of developing the database, a programmer needs to adapt the database system according to the ER diagram to generate various corresponding data tables and database operation codes. In the database maintenance process, operation and maintenance personnel need to maintain the integrity of the database according to the ER diagram, and ensure the stable operation of the database. In the process of reconstructing the database, developers use the ER graph to adapt to new service systems, application scenes and performance requirements, and the effects of application migration and industry upgrading are improved.

Therefore, the ER graph is completely, comprehensively and scientifically drawn and visually presented to the user, and the method has important significance and value in information system construction.

The ER graph is composed of nodes and edges, and the drawing process mainly comprises the drawing of the nodes and the edges. Currently, there are two problems in ER node mapping:

on the one hand, the precedence order of node drawing is problematic. The degree of the node can be regarded as the rich degree of the information associated with the entity, and the node with larger degree is associated with more entities and has rich 'entity-relationship' information; if the nodes with larger degrees are arranged and drawn at the back, little space is left on a drawing interface for the nodes, and the associated information cannot be fully shown.

On the other hand, the spatial location of the node plot is problematic. When a plurality of entities associated with the nodes are drawn, the drawn spatial positions are not unified and specified according to ergonomics, which is not necessarily in line with the aesthetic laws of users and has poor visual perception.

The above problems in node rendering can cause problems of crossing, overlapping, surrounding, etc. in edge rendering. The drawing problems of the nodes and the edges are overlapped, the visual effect is poor, and the user experience is influenced to a certain extent.

In the face of the above problems, a new ER mapping method needs to be designed.

Disclosure of Invention

The invention provides an ER (extract-based) graph drawing method based on adjacency list node states and priorities, which aims to solve the problems of node drawing sequence and node drawing spatial position in the current ER graph drawing and improve the display effect and user experience of ER graph drawing.

The technical scheme of the invention is as follows:

an ER graph drawing method based on adjacency list node state and priority,

the method comprises the following steps:

s1: reading a database table structure;

s2: generating an adjacency list-based entity relationship model;

s3: and (4) drawing an ER graph by combining the node degrees and the visual position priority.

Further, the entity relationship model generated in step S2 has the following features:

s21: the entity represents a data table existing in the database, and the relationship is the relationship type between any two data tables;

s22, the relationship types include 4 types: 1: 1. 1: n, M: 1. m: n, the corresponding type values are 1, 2, 3 and 4 respectively;

s23: each entity corresponds to a node, and an array formed by all the nodes is called a node table of an adjacent table;

s24; each node corresponds to an edge set, and the storage positions of other nodes which have a relationship with the node and the relationship among the nodes are stored;

s25: the set of all node edge sets is called the edge table of the adjacency table.

Further, the step S3 specifically includes:

s31: generating an ordered node table and an ordered edge set; the step S31 specifically includes:

s311: arranging all nodes of the node table in a descending order according to the degree to form an ordered node table;

s312: all elements in the edge set corresponding to each node are arranged in a descending order according to the degree of the corresponding node to form an ordered edge set;

s313: returning the generated ordered node table and ordered edge set;

s32: initializing a node state array VertStatusArray, wherein all element values are 1;

s33: drawing an ER graph; the step S33 specifically includes:

s331: selecting a first node VA in the ordered node table;

s332: determine whether the VertStatusArray [ VA ]! If yes, go to S333, otherwise go to S339;

s333: drawing nodes and connection relations of the VA and the edge set thereof; the step S333 specifically includes:

s3331: determine whether the VertStatusArray [ VA ]! If yes, then go to S3332, otherwise go to S3333;

s3332: drawing a VA in the center above the vacant position of the screen;

s3333: drawing nodes of the VA edge set; the step S3333 specifically includes:

s33331: calculating the node number RA of which the node number DA is already drawn under the node VA and on the horizontal two sides and the VA edge concentration state value is 1;

s33332: judging whether DA is satisfied, if so, turning to S33333, otherwise, turning to S33334;

s33333: completely drawing a node with a VA edge centralized state value of 1 under the node VA and on the horizontal two sides, and turning to 33337; the step S33333 specifically includes:

s33333331: judging whether RA is satisfied, if so, switching to S333332, otherwise, switching to S333333;

s33333332: drawing nodes with RA state values of 1 in the VA edge set right below VA, and turning to S333339;

s33333333: judging whether RA is satisfied, if so, switching to S333334, otherwise, switching to S33333335;

s33333334: drawing RA nodes with state values of 1 in the VA edge set on two horizontal sides of the VA, and turning to S333339;

s33333335: judging whether RA is satisfied, if so, switching to S333336, otherwise, switching to S333337;

s33333336: drawing nodes with RA state values of 1 in the VA edge set right below the VA and on two horizontal sides, and turning to S333339;

s33333337: judging whether RA is satisfied >3, if so, turning to S333338, otherwise, turning to S333339;

s33333338: drawing the first 3 nodes of the VA edge set under VA and on the two horizontal sides, and uniformly drawing the rest RA-3 nodes in a right-angle area formed under VA and on the two horizontal sides;

s33333339: returning the fully drawn nodes;

s33334: judging whether 0< DA <3 is satisfied, if so, turning to S33335, otherwise, turning to S33336;

s33335: drawing a node with a VA edge centralized state value of 1 at the part right below and on the two horizontal sides of the node VA, and turning to S33337; the step S33335 specifically includes:

s33333351: judging whether 0< RA < ═ 3-DA is met, if so, turning to S333352, and otherwise, turning to S333353;

s33333352: drawing nodes with RA state values of 1 in the VA edge set at vacant positions right below the VA and on two horizontal sides, and turning to S333356;

s33333353: judging whether RA is satisfied >3-DA, if so, turning to S333354, and otherwise, turning to S33333356;

s33333354: drawing nodes with the first 3-DA state values of 1 in the VA edge set at vacant positions right below the VA and on the two horizontal sides;

s33333355: uniformly drawing the rest nodes with the state value of 1 of RA-3+ DA in the VA edge set in a right-angle area formed under the VA and on the horizontal two sides;

s33333356: returning the partially drawn nodes;

s33336: uniformly drawing a node with a VA edge centralized state value of 1 in a right-angle area around a node VA; the step S33336 specifically includes:

s33333361: judging whether RA is satisfied >0, if so, turning to S333362, otherwise, turning to S333363;

s33333362: uniformly drawing RA nodes with state values of 1 in the VA edge set in a right-angle area formed right below the VA and on the horizontal two sides;

s33333363: returning the uniformly drawn nodes;

s33337: returning the drawn VA edge aggregation point;

s3334: drawing the connection relation between the VA and the edge aggregation point thereof; the step S3334 specifically includes:

s33341: acquiring the position Loc _ VA of the VA in the ER diagram;

s33342: reading an edge set EdgeSetRTA corresponding to VA;

s33343: reading a first element PTRT _ VB of the EdgeSetRTA;

s33344: acquiring a corresponding node pointer PT _ VB and a relation type RT _ VB from the PTRT _ VB;

s33345: acquiring a corresponding node VB according to the PT _ VB;

s33346: acquiring a position Loc _ VB of VB in an ER diagram;

s33347: drawing a Line segment Line _ AB from Loc _ VA to Loc _ VB;

s33348: marking the relation type at two ends of Line _ AB according to RT _ VB;

s33349: returning the drawn connection relation;

s3335: modifying the state value of the node with the VA edge set state value of 1 to 2;

s3336: modifying the node VA state VertStatusArray [ VA ] ═ 3;

s3337: returning the drawn VA edge aggregation point and connection relation;

s334: selecting a first node VB in the VA edge set;

s335: determine whether the VertStatusArray VB is satisfied! If 3, go to S336, otherwise go to S337;

s336: drawing nodes and connection relations of VB and the edge sets thereof; the step S336 specifically includes:

s3361: determine whether the VertStatusArray VB is satisfied! If yes, then go to S3362, otherwise go to S3363;

s3362: drawing VB at the center above the vacant position of the screen;

s3363: drawing nodes of the VB edge set; the step S3363 specifically includes:

s33631: calculating the node number RB which is under the node VB and on the horizontal two sides of the node DB and has a VB edge centralized state value of 1;

s33632: judging whether DB is 0 or not, if so, turning to S33633, otherwise, turning to S33634;

s33633: completely drawing a node with a VB edge centralized state value of 1 under the node VB and on the two horizontal sides, and turning to S33637; the step S33633 specifically includes:

s336331: judging whether RB is 1 or not, if so, turning to S336332, and otherwise, turning to S336333;

s336332: drawing RB nodes with the state values of 1 in the VB edge set right below VB, and turning to S336339;

s336333: judging whether RB is 2 or not, if so, turning to S336334, and otherwise, turning to S336335;

s336334: drawing RB nodes with the state values of 1 in the VB edge set on two horizontal sides of the VB, and turning to S336339;

s336335: judging whether RB is satisfied, if so, turning to S336336, otherwise, turning to S336337;

s336336: drawing nodes with RB state values of 1 in the VB edge set right below VB and on two horizontal sides, and turning to S336339;

s336337: judging whether RB >3 is met, if so, turning to S336338, and otherwise, turning to S336339;

s336338: drawing the first 3 nodes of the VB edge set under VB and on the two horizontal sides, and uniformly drawing the rest RB-3 nodes in a right-angle area formed under VB and on the two horizontal sides;

s336339: returning the fully drawn nodes;

s33634: judging whether 0< DB <3 is satisfied, if so, turning to S33635, otherwise, turning to S33636;

s33635: drawing nodes with the VB edge centralized state value of 1 under the VB and on the horizontal two side parts of the node, and turning to S33637; the step S33635 specifically includes:

s336351: judging whether 0< RB < ═ 3-DB is met, if yes, turning to S336352, and otherwise, turning to S336353;

s336352: drawing RB nodes with the state values of 1 in the VB edge set at vacant positions right below VB and on two horizontal sides, and turning to S336356;

s336353: judging whether RB >3-DB is met, if yes, turning to S336354, and if not, turning to S336356;

s336354: drawing nodes with the state values of 1 in the first 3-DB in the VB edge set at the vacant positions right below VB and on the two horizontal sides;

s336355: uniformly drawing nodes with state values of 1 of the rest RB-3+ DB in the VB edge set in a right-angle area formed under the VB and on the two horizontal sides;

s336356: returning the partially drawn nodes;

s33636: uniformly drawing nodes with a VB edge concentration state value of 1 in a right-angle area around the node VB; the step S33636 specifically includes:

s336361: judging whether RB >0 is met, if so, turning to S336362, and otherwise, turning to S336363;

s336362: uniformly drawing RB nodes with the state values of 1 in the VB edge set in a right-angle area formed right below VB and on the two horizontal sides;

s336363: returning the uniformly drawn nodes;

s33637: returning the drawn VB edge aggregation point;

s3364: drawing the connection relation between VB and the edge aggregation point thereof; the step S3364 specifically includes:

s33641: acquiring a position Loc _ VB of VB in an ER diagram;

s33642: reading an edge set EdgeSetRTB corresponding to VB;

s33643: reading a first element PTRT _ VC of the EdgeSetRTB;

s33644: acquiring a corresponding node pointer PT _ VC and a relation type RT _ VC from the PTRT _ VC;

s33645: acquiring a corresponding node VC according to PT _ VC;

s33646: acquiring a position Loc _ VC of the VC in the ER diagram;

s33647: drawing a Line segment Line _ BC from Loc _ VB to Loc _ VC;

s33648: marking the relation types at two ends of Line _ BC according to RT _ VC;

s33649: returning the drawn connection relation;

s3365: modifying the state value of the node with the VB edge concentration state value of 1 into 2;

s3366: modifying the node VB state VertStatusArray [ VB ] to be 3;

s3367: returning the drawn VB edge aggregation point and connection relation;

s337: judging whether the reading of the nodes of the VA edge set is finished, if not, turning to S338, otherwise, turning to S339;

s338: reading the next node VB of the VA edge set, and turning to S335;

s339: judging whether the reading of the ordered node table is finished, if not, turning to S33A, otherwise, turning to S33B;

S33A: reading the next node VA of the ordered node table, and switching to S32;

S33B: the rendered ER map is returned.

In addition, the invention also provides an ER graph drawing device based on the adjacency list node state and priority, which comprises:

a table structure reading means M1 for reading a table structure of the database;

an entity relationship model generation component M2, configured to store entities and relationship types existing in the database in an adjacency table;

and the ER drawing component M3 is used for drawing the entity relation model stored by adopting the adjacency list.

Wherein the ER map drawing unit M3 specifically includes:

an adjacency list ordering unit M31 for generating an ordered node list and an ordered edge set;

and an adjacency list drawing part M32 for drawing nodes and connection relations of the adjacency list.

The adjacency list drawing unit M32 specifically includes:

a class 1 node and relationship drawing component M321 for drawing nodes of the node table and nodes of the edge set thereof, and a connection relationship between the two;

and a node and relationship drawing part of type 2M 322, configured to draw nodes of the edge set, nodes of the edge set corresponding to the node table, and a connection relationship between the nodes and the edge set.

The invention has the advantages that

The nodes are arranged in descending order according to the illumination, the nodes are drawn one by one according to the arrangement order, enough nodes with larger space drawing systems can be possessed, and rich entity-relationship information of the nodes can be fully displayed; the drawing sequence of the node-associated entities is arranged according to the visual perception smooth perception principle and the distribution condition of the drawn associated entities at the adjacent positions of the nodes, so that the basic reading habit of a user is met, and the fluency and the pleasure of the user in reading the ER graph can be improved.

Drawings

FIG. 1 is a flow chart of the steps of the method of the present invention;

FIG. 2 is an example of storing a mockup model using adjacency tables;

fig. 3 is a flowchart showing the detailed steps of step S3;

fig. 4 is a flowchart showing the detailed steps of step S31;

FIG. 5 is an example of an entity relationship model after ordering node tables and edge sets;

fig. 6 is a flowchart of the detailed steps of step S33;

fig. 7 is a flowchart of the detailed steps of step S333;

fig. 8 is a flowchart illustrating the detailed steps of step S3333;

fig. 9 is a flowchart showing the detailed steps of step S33333;

FIG. 10 is a flowchart illustrating the detailed steps of step S33335;

fig. 11 is a flowchart illustrating specific steps of step S33336;

fig. 12 is a flowchart showing the detailed steps of step S3334;

FIG. 13 is an example of nodes and connections for plotting VA and its edge sets;

fig. 14 is a flowchart showing the detailed steps of step S336;

fig. 15 is a flowchart showing the detailed steps of step S3363;

fig. 16 is a flowchart of the detailed steps of step S33633;

fig. 17 is a flowchart of the detailed steps of step S33635;

FIG. 18 is a flowchart illustrating the detailed procedure of step S33636;

fig. 19 is a flowchart showing the detailed steps of step S3364;

FIG. 20 is an example of nodes and connections plotting VB and its edge set;

FIG. 21 is an ER plot result example;

FIG. 22 is a block diagram of the structure of the apparatus of the present invention;

fig. 23 is a block diagram of the structure of the ER map drawing part M3;

fig. 24 is a block diagram of the structure of the adjacency list drawing unit M32.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer and more complete, the technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention, and based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the scope of the present invention.

The invention is realized by the following scheme: an ER graph drawing method based on adjacency list node status and priority, as shown in fig. 1, includes the following steps:

s1: reading a database table structure;

s2: generating an adjacency list-based entity relationship model;

FIG. 2 is a block diagram of an entity relationship model stored using adjacency lists, recording entities and relationship types present in a database consisting of { student list, course list, student achievement list, teacher teaching list }. The model is composed of two parts:

a. node table

The data table is regarded as nodes, and the one-dimensional array formed by the nodes is called a node table, as shown in a sequence formed by 5 nodes from the top to the bottom at the leftmost side of the graph 2. Each node record of the node table corresponds to table structure information, including table name, attribute name array, main key and foreign key; the attribute name array element stores the name of each attribute, and the main key and the foreign key are arrays and respectively store the attribute names corresponding to the main key and the foreign key.

In fig. 2, a sequence [ student list, course list, student achievement list, teacher list, and teacher teaching list ] composed of 5 nodes from the top to the bottom on the leftmost side is the node list of the model. The table structure information of the node "curriculum schedule" record is shown in table 1.

TABLE 1 TABLE STRUCTURE INFORMATION OF TABLE-LOOKING RECORDS

Attribute name	Main key	External key
			Course numbering	Y	N
Course name	N	N
			School time	N	N

b. Edge table

For each node in the node table, storing the storage position of the other node in the edge containing the node and the relationship type between the two by adopting a pointer linked list, and forming an edge set of the node; the set of edge sets for all nodes is called the edge table of the adjacency table. The relationship type between two nodes is the relationship type between corresponding data tables, and for convenience of representation, the value ranges of the relationship types are defined as 1, 2, 3 and 4, and respectively represent 1: 1. 1: n, M: 1. m: and N is added.

In fig. 2, a linked list pointed by an arrow on the right side of a node "curriculum schedule" forms an edge set { [ student achievement table, 2], [ teacher teaching table, 2] }, and the edge set indicates that the "curriculum schedule" and the "student achievement table", "curriculum schedule" and the "teacher teaching table" all have an association relationship, and the types are all 1: n (corresponding values are all 2).

Further, as shown in fig. 3, the step S3 specifically includes:

s31: generating an ordered node table and an ordered edge set;

further, as shown in fig. 4, the step S31 specifically includes:

s313: and returning the generated ordered node table and the ordered edge set.

The above operation is performed on the adjacency list shown in fig. 2, and the result is shown in fig. 5.

s33: ER plots were plotted.

Further, as shown in fig. 6, the step S33 specifically includes:

s331: selecting a first node VA in the ordered node table;

s333: drawing nodes and connection relations of the VA and the edge set thereof;

further, as shown in fig. 7, the step S333 specifically includes:

s3332: drawing a VA in the center above the vacant position of the screen;

s3333: drawing nodes of the VA edge set;

further, as shown in fig. 8, the step S3333 specifically includes:

s33333: completely drawing a node with a VA edge centralized state value of 1 under the node VA and on the horizontal two sides, and turning to 33337;

further, as shown in fig. 9, the step S33333 specifically includes:

s33333339: and returning to the fully drawn nodes.

s33335: drawing a node with a VA edge centralized state value of 1 at the part right below and on the two horizontal sides of the node VA, and turning to S33337;

further, as shown in fig. 10, the step S33335 specifically includes:

s33333356: and returning the partially drawn nodes.

S33336: uniformly drawing a node with a VA edge centralized state value of 1 in a right-angle area around a node VA;

further, as shown in fig. 11, the step S33336 specifically includes:

s33333363: and returning the uniformly drawn nodes.

S33337: and returning to the drawn VA edge aggregation point.

S3334: drawing the connection relation between the VA and the edge aggregation point thereof;

further, as shown in fig. 12, the step S3334 specifically includes:

s33341: acquiring the position Loc _ VA of the VA in the ER diagram;

s33342: reading an edge set EdgeSetRTA corresponding to VA;

s33343: reading a first element PTRT _ VB of the EdgeSetRTA;

s33345: acquiring a corresponding node VB according to the PT _ VB;

s33346: acquiring a position Loc _ VB of VB in an ER diagram;

s33347: drawing a Line segment Line _ AB from Loc _ VA to Loc _ VB;

s33349: and returning the drawn connection relation.

s3336: modifying the node VA state VertStatusArray [ VA ] ═ 3;

s3337: and returning the drawn VA edge aggregation point and connection relation.

In fig. 5, the first node VA in the ordered node table is "curriculum schedule", the nodes in the edge set include "student achievement table" and "teacher teaching table", and the above operation is performed on the nodes shown in fig. 5, and the drawing result is shown in fig. 13.

S334: selecting a first node VB in the VA edge set;

s336: drawing nodes and connection relations of VB and the edge sets thereof;

further, as shown in fig. 14, the step S336 specifically includes:

s3362: drawing VB at the center above the vacant position of the screen;

s3363: drawing nodes of the VB edge set;

further, as shown in fig. 15, the step S3363 specifically includes:

s33633: completely drawing a node with a VB edge centralized state value of 1 under the node VB and on the two horizontal sides, and turning to S33637;

further, as shown in fig. 16, the step S33633 specifically includes:

s336339: and returning to the fully drawn nodes.

s33635: drawing nodes with the VB edge centralized state value of 1 under the VB and on the horizontal two side parts of the node, and turning to S33637;

further, as shown in fig. 17, the step S33635 specifically includes:

s336356: and returning the partially drawn nodes.

S33636: uniformly drawing nodes with a VB edge concentration state value of 1 in a right-angle area around the node VB;

further, as shown in fig. 18, the step S33636 specifically includes:

s336363: and returning the uniformly drawn nodes.

S33637: and returning to the VB edge aggregation point.

S3364: and drawing the connection relation between VB and the edge aggregation point thereof.

Further, as shown in fig. 19, the step S3364 specifically includes:

s33641: acquiring a position Loc _ VB of VB in an ER diagram;

s33642: reading an edge set EdgeSetRTB corresponding to VB;

s33643: reading a first element PTRT _ VC of the EdgeSetRTB;

s33645: acquiring a corresponding node VC according to PT _ VC;

s33646: acquiring a position Loc _ VC of the VC in the ER diagram;

s33647: drawing a Line segment Line _ BC from Loc _ VB to Loc _ VC;

s33649: and returning the drawn connection relation.

s3366: modifying the node VB state VertStatusArray [ VB ] to be 3;

s3367: and returning the drawn VB edge aggregation point and the connection relation.

In fig. 5, the first node VB is a "student performance table" in the edge set of the node VA "curriculum schedule", and the edge set point thereof includes the "curriculum schedule" and the "student schedule", and the above operation is performed on the basis of fig. 13, and the result is plotted as shown in fig. 20.

s338: reading the next node VB of the VA edge set, and turning to S335;

S33A: reading the next node VA of the ordered node table, and switching to S32;

S33B: the rendered ER map is returned.

The above operations are performed on the basis of fig. 20, the nodes "teacher lecture table", "student table" and "teacher table" are selected in sequence, the nodes and the connection relations of the nodes and the edge sets thereof are respectively drawn, and the drawing result is shown in fig. 21.

An ER graph drawing apparatus based on adjacency list node status and priority according to the present invention, as shown in fig. 22, includes:

an ER mapping unit M3 for mapping a solid relational model stored using an adjacency table, as shown in fig. 23, the ER mapping unit M3 including:

an adjacency list drawing unit M32 configured to draw nodes of an adjacency list and their connection relationships, as shown in fig. 24, the adjacency list drawing unit M32 includes:

The above description is only a preferred embodiment of the present invention, and is only used to illustrate the technical solutions of the present invention, and not to limit the protection scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. An ER graph drawing method based on adjacency list node state and priority is characterized in that,

the method comprises the following steps:

s1: reading a database table structure;

s2: generating an adjacency list-based entity relationship model;

2. The method according to claim 1, wherein the entity-relationship model generated in step S2 has the following characteristics:

an entity represents a data table that exists in a database, and a relationship is a type of relationship between any two data tables.

3. The method of claim 2,

the relationship types include 4 types: 1: 1. 1: n, M: 1. m: and N, wherein the corresponding type values are 1, 2, 3 and 4 respectively.

4. The method of claim 3,

each entity corresponds to a node, and an array formed by all the nodes is called a node table of an adjacent table;

each node corresponds to an edge set, and the storage positions of other nodes which have a relationship with the node and the relationship among the nodes are stored;

the set of all node edge sets is called the edge table of the adjacency table.

5. The method of claim 1, wherein: the step S3 specifically includes:

s313: returning the generated ordered node table and ordered edge set;

s33: drawing an ER graph; the step S33 specifically includes:

s331: selecting a first node VA in the ordered node table;

s3332: drawing a VA in the center above the vacant position of the screen;

s3333: drawing nodes of the VA edge set; the step S3333 specifically includes:

s33333339: returning the fully drawn nodes;

s33333356: returning the partially drawn nodes;

s33333363: returning the uniformly drawn nodes;

s33337: returning the drawn VA edge aggregation point;

s33341: acquiring the position Loc _ VA of the VA in the ER diagram;

s33342: reading an edge set EdgeSetRTA corresponding to VA;

s33343: reading a first element PTRT _ VB of the EdgeSetRTA;

s33345: acquiring a corresponding node VB according to the PT _ VB;

s33346: acquiring a position Loc _ VB of VB in an ER diagram;

s33347: drawing a Line segment Line _ AB from Loc _ VA to Loc _ VB;

s33349: returning the drawn connection relation;

s3336: modifying the node VA state VertStatusArray [ VA ] ═ 3;

s3337: returning the drawn VA edge aggregation point and connection relation;

s334: selecting a first node VB in the VA edge set;

s3362: drawing VB at the center above the vacant position of the screen;

s3363: drawing nodes of the VB edge set; the step S3363 specifically includes:

s336339: returning the fully drawn nodes;

s336356: returning the partially drawn nodes;

s336363: returning the uniformly drawn nodes;

s33637: returning the drawn VB edge aggregation point;

s33641: acquiring a position Loc _ VB of VB in an ER diagram;

s33642: reading an edge set EdgeSetRTB corresponding to VB;

s33643: reading a first element PTRT _ VC of the EdgeSetRTB;

s33645: acquiring a corresponding node VC according to PT _ VC;

s33646: acquiring a position Loc _ VC of the VC in the ER diagram;

s33647: drawing a Line segment Line _ BC from Loc _ VB to Loc _ VC;

s33649: returning the drawn connection relation;

s3366: modifying the node VB state VertStatusArray [ VB ] to be 3;

s3367: returning the drawn VB edge aggregation point and connection relation;

s338: reading the next node VB of the VA edge set, and turning to S335;

S33A: reading the next node VA of the ordered node table, and switching to S32;

S33B: the rendered ER map is returned.

6. An ER graph drawing device based on adjacency list node states and priorities, comprising:

7. The apparatus of claim 6, wherein: the ER map drawing unit M3 specifically includes:

8. The apparatus of claim 7, wherein:

the adjacency list drawing unit M32 specifically includes: