1. 简介

2. 如何使用SchemaRepository

3. Column Resolve

final String dbType = JdbcConstants.MYSQL;
 
SchemaRepository repository = new SchemaRepository(dbType);
 
repository.console("create table t_emp(emp_id bigint, name varchar(20));");
repository.console("create table t_org(org_id bigint, name varchar(20));");
 
String sql = "SELECT emp_id, a.name AS emp_name, org_id, b.name AS org_name\n" +
        "FROM t_emp a\n" +
        "\tINNER JOIN t_org b ON a.emp_id = b.org_id";
 
List<SQLStatement> stmtList = SQLUtils.parseStatements(sql, dbType);
 
SQLSelectStatement stmt = (SQLSelectStatement) stmtList.get(0);
SQLSelectQueryBlock queryBlock = stmt.getSelect().getQueryBlock();
 
// 大小写不敏感
assertNotNull(queryBlock.findTableSource("A"));
assertSame(queryBlock.findTableSource("a"), queryBlock.findTableSource("A"));
 
assertNull(queryBlock.findTableSourceWithColumn("emp_id"));
 
// 使用repository做column resolve
repository.resolve(stmt);
 
assertNotNull(queryBlock.findTableSourceWithColumn("emp_id"));
SQLExprTableSource tableSource = (SQLExprTableSource) queryBlock.findTableSourceWithColumn("emp_id");
assertNotNull(tableSource.getSchemaObject());
 
SQLCreateTableStatement createTableStmt = (SQLCreateTableStatement) tableSource.getSchemaObject().getStatement();
assertNotNull(createTableStmt);
 
SQLSelectItem selectItem = queryBlock.findSelectItem("org_name");
assertNotNull(selectItem);
SQLPropertyExpr selectItemExpr = (SQLPropertyExpr) selectItem.getExpr();
SQLColumnDefinition column = selectItemExpr.getResolvedColumn();
assertNotNull(column);
assertEquals("name", column.getName().toString());
assertEquals("t_org", (((SQLCreateTableStatement)column.getParent()).getName().toString()));